A meta-analysis of diffusion tensor imaging studies of the corpus callosum in schizophrenia

Background: The corpus callosum has been hypothesized to play an important role in neurobiological models of schizophrenia. Diffusion tensor imaging studies have provided evidence for a disruption in corpus callosum morphology in schizophrenia, but the regional distribution of abnormalities is not well known. Methods: We conducted 2 meta-analyses investigating the genu and splenium of the corpus callosum in schizophrenia, respectively, based on published diffusion tensor imaging studies that employed a region-of-interest approach. Seven studies investigating the genu and splenium involving a total of 202 patients with schizophrenia and 213 healthy volunteers were included. Results: The meta-analysis of the genu yielded an effect size of 0.223 and was not statistically significant. The second meta-analysis investigating the splenium yielded a modest effect size of 0.527 (p = 0.001), indicating that patients had lower fractional anisotropy in this region compared to healthy volunteers. Studies that included fewer men had a larger effect size for the splenium. Discussion: These findings implicate an abnormality involving the splenium of the corpus callosum in the neurobiology of schizophrenia as inferred by diffusion tensor imaging. A defect in the splenium could contribute to abnormalities in posterior interhemispheric connectivity in patients, including regions of the heteromodal association cortex.